Non-performing Loans and Impaired Loans - Loans by Credit Grades (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Total	$ 1,080,231	$ 1,188,466
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	498,824	459,558
Commercial [Member] | Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	153,113	162,694
Commercial [Member] | Non Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	229,654	201,763
Commercial [Member] | Residential Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	242	1,056
Commercial [Member] | Development & Spec Land Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	15,621	6,963
Commercial [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	100,194	87,082
Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	302,436	440,579
Real Estate [Member] | Residential mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	179,964	181,450
Real Estate [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	8,881	7,681
Real Estate [Member] | Mortgage Warehouse [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	113,591	251,448
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	278,971	288,329
Consumer [Member] | Direct Installment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	28,968	27,831
Consumer [Member] | Direct Installment Purchased [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	331	429
Consumer [Member] | Indirect Installment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	129,450	133,481
Consumer [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	120,222	126,588
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	1,024,587	1,107,191
Percentage of total loans	94.85%	93.16%
Pass [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	457,775	391,369
Pass [Member] | Commercial [Member] | Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	142,836	137,664
Pass [Member] | Commercial [Member] | Non Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	210,632	171,319
Pass [Member] | Commercial [Member] | Residential Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	242	405
Pass [Member] | Commercial [Member] | Development & Spec Land Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	13,844	3,171
Pass [Member] | Commercial [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	90,221	78,810
Pass [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	294,343	431,424
Pass [Member] | Real Estate [Member] | Residential mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	172,155	172,586
Pass [Member] | Real Estate [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	8,597	7,390
Pass [Member] | Real Estate [Member] | Mortgage Warehouse [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	113,591	251,448
Pass [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	272,470	284,398
Pass [Member] | Consumer [Member] | Direct Installment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	28,719	27,667
Pass [Member] | Consumer [Member] | Direct Installment Purchased [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	331	429
Pass [Member] | Consumer [Member] | Indirect Installment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	128,793	132,589
Pass [Member] | Consumer [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	114,627	123,713
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	11,223	29,161
Percentage of total loans	1.04%	2.45%
Special Mention [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	11,223	29,161
Special Mention [Member] | Commercial [Member] | Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	2,600	6,407
Special Mention [Member] | Commercial [Member] | Non Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	3,119	19,440
Special Mention [Member] | Commercial [Member] | Residential Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Special Mention [Member] | Commercial [Member] | Development & Spec Land Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	94	178
Special Mention [Member] | Commercial [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	5,410	3,136
Special Mention [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Special Mention [Member] | Real Estate [Member] | Residential mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Special Mention [Member] | Real Estate [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Special Mention [Member] | Real Estate [Member] | Mortgage Warehouse [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Special Mention [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Special Mention [Member] | Consumer [Member] | Direct Installment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Special Mention [Member] | Consumer [Member] | Direct Installment Purchased [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Special Mention [Member] | Consumer [Member] | Indirect Installment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Special Mention [Member] | Consumer [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	44,420	50,233
Percentage of total loans	4.11%	4.23%
Substandard [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	29,826	37,147
Substandard [Member] | Commercial [Member] | Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	7,677	17,029
Substandard [Member] | Commercial [Member] | Non Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	15,903	10,717
Substandard [Member] | Commercial [Member] | Residential Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Total		651
Substandard [Member] | Commercial [Member] | Development & Spec Land Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	1,683	3,614
Substandard [Member] | Commercial [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	4,563	5,136
Substandard [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	8,093	9,155
Substandard [Member] | Real Estate [Member] | Residential mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	7,809	8,864
Substandard [Member] | Real Estate [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	284	291
Substandard [Member] | Real Estate [Member] | Mortgage Warehouse [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Substandard [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	6,501	3,931
Substandard [Member] | Consumer [Member] | Direct Installment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	249	164
Substandard [Member] | Consumer [Member] | Direct Installment Purchased [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Substandard [Member] | Consumer [Member] | Indirect Installment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	657	892
Substandard [Member] | Consumer [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	5,595	2,875
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total		1,881
Percentage of total loans	0.00%	0.16%
Doubtful [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total		1,881
Doubtful [Member] | Commercial [Member] | Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total		1,594
Doubtful [Member] | Commercial [Member] | Non Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total		287
Doubtful [Member] | Commercial [Member] | Residential Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Doubtful [Member] | Commercial [Member] | Development & Spec Land Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Doubtful [Member] | Commercial [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Doubtful [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Doubtful [Member] | Real Estate [Member] | Residential mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Doubtful [Member] | Real Estate [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Doubtful [Member] | Real Estate [Member] | Mortgage Warehouse [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Doubtful [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Doubtful [Member] | Consumer [Member] | Direct Installment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Doubtful [Member] | Consumer [Member] | Direct Installment Purchased [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Doubtful [Member] | Consumer [Member] | Indirect Installment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total
Doubtful [Member] | Consumer [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total